3D printing apparatus with sensor device

Abstract

The various embodiments herein provide a 3D printing apparatus with a sensor device. The apparatus comprises a base platform, a support frame mounted on the base platform and a print head mounted on the support frame. The print head is aligned with a working surface on which the 3D object to be printed is placed. A sensor device is configured to determine and adjust a spatial parameter between the working surface and a print head. The sensor device is mounted on the print head and detects misalignment in the position of the working surface with the print head. The sensor device employs photo detection method for determining a desired orientation of the working surface. The printing apparatus comprises a controller unit for receiving the input from the sensor device to correct the orientation of the working surface.

What is claimed is:  
     
       1. A three-dimensional (3-D) printer comprising a print head and a print bed, a positioning system configured to displace the print head and print bed relative to each other, the tilt between the axis of the print head and print bed being adjustable;
 a calibrated sensor device having a light source, at least three photo detectors and an output, 
 
       the light source emitting a beam, the beam directed towards a reflecting surface, the beam reflecting from the surface, the detectors configured to detect the reflecting beam, the detectors of the sensor device generating an output signal, the output of the sensor device connected to a processor, 
       the processor loaded with software having an algorithm; 
       the algorithm used to calculate a tilt correcting output; 
       the output sent to a print bed tilt adjustment means to adjust the tilt between the print head and the print bed; 
       so that at any stage that is, before, during, and after the printing process upon activation the light source emits a beam that is reflected from the reflecting surface and detected by the detectors, the detectors of the sensor device then generating an output signal that is used by the processor to calculate a tilt correcting output which is sent to the print bed tilt adjusting means, which then adjusts the tilt between the print head and print bed,
 wherein the algorithm includes the following steps: 
 grouping the output signal of the detectors, into a max group containing the detectors having a high reading output and 
 into min group containing the light detectors having a low reading output and then using a look-up table to calculate the tilt correcting output. 
 
     
     
       2. The 3-D printer as in  claim 1  wherein the sensor device comprises a sensor board containing the emitter and detectors, the emitter and detector directed in the same direction. 
     
     
       3. The 3-D printer as in  claim 1  alternatively  claim 2 , wherein the sensor device is attached to the print head and directed to the print bed. 
     
     
       4. The 3-D printer as in  claim 1  alternatively  claim 3  wherein the reflective surface is the surface of the print bed. 
     
     
       5. The 3-D printer as in  claim 1  wherein the sensor device is calibrated by;
 placing a test reflective surface perpendicular to the sensor device; 
 activating the light source with a pulsed signal so that the light source emits a pulsed beam towards the test reflective surface and is reflected so that it is detected by a detector to be calibrated; 
 increasing the time duration of the pulse signal so that the light source correspondingly emits a pulsed beam of increasing time duration; 
 until the detector output reaches a selected value, within the working range of the detector; thereby associating a certain light source pulse width with the detector; 
 repeating the same procedure with the other detectors in the sensor device until the same selected value has been reached and so a certain pulse width is associated with each of the detectors; 
 using the pulse width associated with each detector to determine a correction multiplier for each detector to be used by the processor and so normalize the output of each detector relative to each other. 
 
     
     
       6. The 3-D printer as in  claim 1  wherein the light source is an infra-red light emitting diode and the detector is an infra-red detector. 
     
     
       7. The 3-D printer as in  claim 1  wherein a reflective surface is mounted on the print bed to reflect the beam of the light source towards the detectors. 
     
     
       8. The 3-D printer as in  claim 1  wherein the print bed tilt adjustment means has two actuators and a mount;
 the actuators having two ends; the one end connected to the mount the other end connected to the print bed; 
 so that when a actuator is activated the tilt of the print bed is adjusted. 
 
     
     
       9. The 3-D printer as in  claim 8  wherein the actuator comprises a stepper motor, the base of the motor being the first end, the stepper motor having a threaded shaft and
 a cylindrical member with an inner threaded bore, the motor shaft entering the cylindrical member from one side and the thread on the shaft engaging the thread of the cylindrical member, the other side of the cylindrical member being the second end; so that when the motor shaft rotates the cylindrical member is displaced along the shaft of the motor, and the first and second ends are displaced relative to each other. 
 
     
     
       10. A print bed tilt adjustment system for a 3-D printer comprising a calibrated sensor device having a light source, at least three photo detectors and an output,
 the light source emitting a beam, the beam directed towards a reflecting surface, the beam reflecting from the reflecting surface and the detectors configured to detect the reflecting beam, the sensor device generating an output signal, which is connected to a processor, 
 the processor loaded with software having an algorithm; 
 to calculate a tilt correcting output; 
 the output connected to a print bed tilt adjustment means; 
 to adjust the tilt between the print head and the print bed; 
 so that at any stage that is, before, during, and after the printing process upon activation the light source emits a beam that is reflected from the reflecting surface and detected by the detectors of the sensor device, the detectors then generating an output signal that is used by the processor to calculate a tilt correcting output which is sent to the print bed tilt adjusting means, which then adjusts the tilt between the print head and print bed; 
 wherein the algorithm includes the following steps: 
 grouping the output signal of the detectors, into a max group containing the detectors having a high reading output and 
 into a min group containing the light detectors having a low reading output and then using a look-up table to calculate the tilt correcting output.